There are many types of child resistant closure systems disclosed in the art. An example of a particular type of child resistant closure system is disclosed in U.S. Pat. No. 5,449,078, which relates to a combination of a container and safety cap. While many child resistant caps effectively provide protection against the danger of small children being able to remove potentially harmful pills from vials or other containers, they also provide a problem for a considerable portion of the adult population that require medication who lack the manual dexterity or strength to remove the child resistant cap. This is of a particular concern to the elderly population or people suffering from arthritis and other disabling diseases.
The most popular type of child-resistant closure is known in the art as a continuous threaded, torque actuated child resistant closure. These caps involve the use of two parts, one of which rests above the other in an axial configuration and which requires both a rotational and downward action to engage for removal. These are used in literally thousands of various applications and packaging configurations due to the universally understood push and turn mechanisms and ease of use and adaptation in a wide variety of automated filing lines and processes. They have become the most prominent and widely accepted solution for packaging requiring child resistant closures. Therefore, any invention designed to overcome the difficulty many senior members of the population experience when attempting to open child-resistant closures should involve, as the basis of its design, a standard two piece, push and turn, torque actuated continuous threaded closure due to their popularity and universal use.
This particular problem has been addressed by the development of closure systems having a child resistant mode and a non-child resistant mode such that, in the non-child resistant mode, the closures are more easily opened by adults. Another example of such a closure is disclosed in U.S. Pat. No. 5,579,934, (the '934 patent) which is herein incorporated by reference. The '934 patent discloses a container closure that is selectively manipulable between a configuration which resists opening by children and a configuration which may be easily opened without special manipulation of the closure. Specifically, the closure is manipulated into its non-child resistant mode by “pressing down” on the central portion of the top surface of the closure. Although the aforementioned closure effectively provides protection against the danger of small children being able to remove it from vials or other containers, a certain portion of the adult population lack the manual dexterity or strength to “press down” the central portion of the top surface of the closure so to manipulate the closure from its child resistant configuration to its non-child resistant configuration. This manipulation or “pushing down” also represents a problem for people with long fingernails. Other reversible child resistant closures have been developed to address this problem. But making the closure easier to convert into the non-child resistant configuration increases the risk that the closures will inadvertently be converted into their non-child resistant configurations. Similarly, there is an increased risk that automated filling machines will inadvertently convert the closures into their non-child resistant configurations when applying the closure to the container.
Further, the closures of the type disclosed in the '934 patent cannot include a warning to the consumer once the closure has been converted to its non-child resistant configuration. This message is required by the Consumer Product Safety Commission (“CPSC”) to alert users that the closure has been converted into the non-child resistant configuration. Also, other reversible child resistant designs that do include the CPSC consumer warning cannot be used in automated dispensing equipment due to projections on their outer surface.
Furthermore, in child resistant caps comprising two or more elements such as an inner cap element nested within an outer cap element, and equipped with an engaging means for rotatably coupling one element to the other such as disclosed in U.S. Pat. No. 4,520,938, the inventors have observed that where the outer cap is made of resilient material such as plastic, a risk exists that children could separate one cap from the other thereby disabling the child resistance mode of operation. This process is known as “shelling” whereby the outer cap is rotated inward with a child's fingers and or teeth under one edge until it pops off, leaving the inner cap exposed. Moreover, as is most often the case in the prior art, the torque required to disengage the closure in the child resistant configuration is invariably the same torque applied to engage the closure in the first place. This means that without an indicator showing that full and complete closure has been attained, an elderly or infirm person could leave such caps partially closed in the child resistant mode thereby exposing it to the risk that a child could disengage the cap even though it had been supposedly closed in the child-resistant mode. When a complete closure indicator is incorporated, it ensures that not only will a user know when the closure is fully closed, but also that a minimal torque threshold would be needed to disengage the complete closure indicator before rotatably removing the closure from the container.
In light of the foregoing, there is a need for a continuous threaded, torque actuated child resistant closure that has a child resistant mode which resists opening by children, is not susceptible to shelling, has a non-child resistant mode which may be easily opened without special manipulation, resists inadvertent conversion from its child resistant mode to its non-child resistant mode, incorporates a mechanism to ensure both complete closing and minimal torque threshold requirements for opening, is capable of including the mandated CPSC warning “CAUTION NOT CHILD RESISTANT” when used in its non-child resistant mode, and can be used in automated dispensing machines so as to overcome the aforementioned deficiencies of the prior art.